Abstract
Inspired by the green communication trend of next-generation wireless networks, we present an opportunistic energy-efficient cooperative communication method. Different from classical relaying selection schemes, which adopt either end-to-end signal-to-noise ratio or capacity as selection metrics, our opportunistic relaying scheme uses an energy efficiency metric for selecting the best relay or resorting to direct transmission. Simulation results demonstrate the significant energy savings achieved by our scheme when compared with opportunistic decode-and-forward based on capacity. In addition to that, dynamic time allocation and increasing the number of participating relays are shown to have a notable effect on energy efficiency.